Electric infrared emitter



Febv2 1%? ,G-r'ZHORSTMANN 3,307,017 ELECTRIC: INFRARED EMITTER FiledJuly 1, 1964 FIG. 2.

INVENTOR B GEORG HORSTMANN w wwa ATTORNEYS.

United States Patent Claims The present invention relates to electricinfrared emitters of the type which comprises emitter or radiating tubesof quartz glass, quartz ware, or a glass of a high melting point andelectric heating coils enclosed within these tubes.

Infrared emitters of the above-mentioned type are frequently employed,for example, for room heating and drying purposes. In most of theseinfrared emitters the heating coils lie loosely within the radiatingtubes and their position in these tubes is not fixed by any fillingmaterial or other securing means. These emitters are employedindividually or in the form of two or more of them adjacent to eachother, for example, in the form of pairs, the heating coils of which areelectrically connected to each other at one end so that the heating coilof one radiating tube serves as the outgoing conductor and the otherheating coil as the return conductor of the electric current. All ofthese infrared emitters are preferably operated in a substantiallyhorizontal position since due to the loose condition of the heatingcoils within the radiating tubes, the weight of these coils, and thehigh temperature of operation, there is a considerable danger that theheating coils will sag downwardly and the individual turns of a coilwill engage with each other and the coil will therefore burn throughwithin a short time.

It is an object of the present invention to provide an infrared emitterwhich overcomes this serious disadvantage of the conventional infraredemitters as described above and which comprises at least two closelyadjacent radiating elements, each of which consists of a tube of quartzglass, quartz ware, or a glass of a high melting point and of a heatingcoil within each of these tubes. According to the invention this objectis attained in a very simple manner by twisting the radiating tubestogether like a rope about a common axis.

Another feature of the invention consists in fusing the twistedradiating tubes together at least at certain points along their lines orsurfaces of engagement and preferably along their entire length.

The present invention also permits the radiating tubes of an infraredemitter to be made of different materials. Thus, for example, oneradiating tube of an emitter with two tubes may consist of quartz glass,while the other radiating tube may consist of quartz ware. The threedilferent materials, quartz glass, quartz ware, and glass of a highmelting point may, of course, also be employed in any other combinationwith each other.

The features and advantages of the present invention will become furtherapparent from the following description of two preferred embodimentsthereof which are illustrated in the accompanying drawings, in which:

FIGURE 1 shows a perspective view of an infrared emitter with tworadiating elements; while FIGURE 2 shows a perspective view of aninfrared emitter with four radiating elements.

The infrared emitter according to the invention as illustrated in FIGURE1 comprises two radiating elements consisting of a pair of individualtubes 1 and 1 of quartz glass, quartz ware, or a glass of a high meltingpoint, and of an electric heating coil 3 or 3' in each of these tubes.These heating coils are electrically connected to each other at one endand one coil thus serves as the outgoing conductor and the other as thereturn conductor of the electric current by means of which both coilsare heated. According to the invention, the two tubes 1 and 1' aretwisted together about a common axis 2 like the strands of a rope, andfor increasing the solidity of the unit, they are fused together alongtheir entire length, as may be seen particularly at their upper andlower ends. In this particular embodiment, the two tubes consist of thesame material, for example, quartz ware.

The infrared emitter as illustrated in FIGURE 2 comprises four radiatingelements consisting of two pairs of tubes 10, 10 and 10", 10" which aretwisted together about a common axis 20 and contain the heating coils30, 30', 30", and 30", respectively. The two heating coils of each pairare again connected at one end and serve as outgoing and returnconductors. In this particular embodiment of the invention, one pair oftubes 10 and 10' consists of quartz ware, while the other pair 10" and10" consists of quartz glass.

The infrared emitters according to this invention have the considerableadvantage that they may be mounted in any desired position. Due to thecontinuously changing direction of the twisted radiating tubes, theheating coils are always supported on the inner walls of these tubeseven when the emitter unit is mounted in a perpendicular position. Thereis therefore never any danger that the heating coils might sag and thattheir individual turns might engage with each other.

As can be seen from FIGS. 1 and 2, the individual resistance elementsheating coils 3, 3', 30, 30', 30" and 30", each have helical coiloutside diameters which are approximately equal to the inside diametersof their respectively associated hollow tubes 1, 1', 10, 10', 10", and10", so as to minimize shifting of said heating elements relative totheir enclosing tubes with changes in attitude thereof. Consequently,the twisting of the aforesaid tubes in combination with the lateralconstraint afforded by their inside diameters substantially precludesany movement of the individual coils tending to short circuit theirindividual turns when the emitter is positioned vertically or in anyattitude where the tube twist axis is. inclined to the horizontal.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments, but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed my invention, what I claim is:

1. An electric infrared radiant heat emitter which comprises a pluralityof elongated hollow tubes twisted together about a common longitudinalaxis, said tubes being each made of a material selected from the groupconsisting of glass, quartz glass, and quartz ware, and a helicallycoiled electrical resistance heating element disposed within each ofsaid hollow tubes for support thereby and for connection to a source ofelectricity for energization thereby to generate and emit infraredradiant heat, said heating element having a helical coil outsidediameter approximately equal to the inside diameter of its associatedtube to minimize shifting of said heating element relative to the tubeupon changes in attitude thereof.

2. The electric infrared radiant heat emitter according to claim 1wherein said tubes are fused together along at least one point ofengagement along their common longitudinal axis.

3. The electric infrared radiant heat emitter according to claim 1wherein said tubes are fused together along Patented Feb. 28, 1967v thelength of their mutual engagement about said axis.

4. The electric infrared radiant heat emitter according to claim 1wherein said tubes are made of different materials selected from saidgroup of materials. 7

5. The electric infrared radiant heat emitter according to claim 1wherein at least two of said resistance heating elements areelectrically connected in series.

References Cited by the Examiner UNITED STATES PATENTS 1,119,336 12/1914Ball 338-268 1,671,592 5/1928 Kercher 2l9-523 4 Whitehouse 174-34 X Babb17434 X Vanvor 338-28 Macksoud 338268 X Browne 338241 Lefebvre 338-236FOREIGN PATENTS 6/ 1959 Great Britain.

RICHARD M. WOOD, Primary Examiner.

V. Y. MAYEWSKY, Assistant Examiner.

1. AN ELECTRIC INFRARED RADIANT HEAT EMITTER WHICH COMPRISES A PLURALITYOF ELONGATED HOLLOW TUBES TWISTED TOGETHER ABOUT A COMMON LONGITUDINALAXIS, SAID TUBES BEING EACH MADE OF A MATERIAL SELECTED FROM THE GROUPCONSISTING OF GLASS, QUARTZ GLASS, AND QUARTZ WARE, AND A HELICALLYCOILED ELECTRICAL RESISTANCE HEATING ELEMENT DISPOSED WITHIN EACH OFSAID HOLLOW TUBES FOR SUPPORT THEREBY AND FOR CONNECTION TO A SOURCE OFELECTRICITY FOR ENERGIZATION THEREBY TO GENERATE AND EMIT INFRAREDRADIANT HEAT, SAID